Newbie Needs Backup Body

[fotojennik]

OK, as I enter into the world of wedding photography (and seniors and family), I realize I need a 2nd/backup body at minimum to feel comfortable being the only photographer (although if doing a wedding solo I would definitely try to bring a 2nd shooter).

At this point, I don't think I can swing another 5D Mark II, if I did I would basically be shooting with 2 bodies [5d2] and 2 lenses [35L and 135L] though perhaps I would swing an extra 50/1.4 and 100non-L.

So, for a 2nd body (so I can have 2 attached to me w/ 2 primes) which also counts as a back-up (though I do have an old 20D if the absolute worst happens and I lose both bodies in one fell swoop somehow)....

Would you rather have:

5D Classic <-- gives me 2 FF bodies
7D (used) <-- better AF, crop
50D (used) <-- worst of the 3 but allows me to then add another lens or two to my lineup

The less I spend on a body is more I can put in glass.

Or, since I won't be shooting anything (have 3 opportunites coming up in Sept and October) for a while, should I just wait and hope to be able to snag a good used 5D Mark II to have 2 solid bodies?

So many options!